1,721,094 research outputs found
Secular trend e variazioni diacroniche nel dimorfismo sessuale. Osservazioni sulla popolazione della Sardegna
No full textAssessment of nutritional status in free-living elderly individuals by bioelectrical impedance vector analysis
No full textObjective: The aim of the present research was to examine bioelectrical vector changes in relation to nutritional status in a sample of healthy free-living elderly people.
Methods: The study group consisted of 170 men and women 70 to 99 y of age. Anthropometric and bioelectrical (resistance and reactance, 50 kHz, 800 mu A) measurements were taken. Bioelectrical impedance vector analysis was applied. Nutritional status was determined by the Mini-Nutritional Assessment. Bioelectrical characteristics of normal and undernourished individuals were compared statistically with Hotelling's T(2) test and graphically with 95% probability confidence ellipses.
Results: The impedance and multidimensional approaches showed a clear association. Undernourished subjects had a smaller phase angle (men 5.2 +/- 1.3 versus 5.7 +/- 1.0 degrees, P = 0.027; women 5.0 +/- 1.0 versus 5.4 +/- 0.9 degrees, P = 0.065) than normally nourished subjects.
Conclusion: Bioelectrical impedance vector analysis represents a promising indicator of nutritional status, suitable in screening programs and clinical practice
La composizione corporea nella popolazione della Sardegna. Variabilità sessuale e del ciclo vitale
No full text
Migration of bioelectrical vector in healthy elderly subjects
No full textOBJECTIVE: We describe the effects of aging on the bioelectrical impedance vectors in healthy men and
women.
METHODS: Resistance (R) and reactance (Xc; standard, tetrapolar analysis at 50-kHz frequency) were
measured in 201 volunteers (97 men and 104 women) aged 60 to 89 y. Criteria of exclusion from the
sample were hospitalization within 3 mo before the survey, current medical treatment, physical handicaps,
or other pathologies that might influence the measurements. Stature, weight, and four body circumferences
were also measured, and body mass index was calculated. The values of R and Xc were normalized
for stature (H) and adjusted for body circumferences by means of covariance analysis. Age- and
sex-dependent bioelectrical changes were evaluated by two-factor analysis of variance and Hotelling’s T2
test.
RESULTS: The bioelectrical data of the sample agreed well with the normal reference values of the Italian
population. R/H showed a significant increase with age in both sexes, whereas Xc/H and the phase angle
significantly decreased. The greatest changes occurred in the 70- to 79-y to the 80- to 89-y groups. After
adjustment of the bioelectrical values for body circumferences, only Xc/H and the phase angle showed
significant differences that decreased with age.
CONCLUSIONS: The impedance vectors of healthy individuals showed a clear trend in the elderly, in both
sexes, and particularly after age 80 y. The bioelectrical parameters indicated a reduction of soft tissue
mass with age, as they tended to approach values typical of pathologically lean subjects (cachetic and
anorexic states). After adjustment for the circumferences, the changes in the vector concerned only the Xc
component, a measure of the capacitance produced by cell membranes of soft tissues. Therefore, in addition to the quantitative change, the electrical properties of the tissues may also change
Variations in sexual dimorphism in relation to physical activity
No full textThe aim of this study was to examine variations in sexual dimorphism in relation to physical activity. A sample of 542 males and females (20-30 years), born and resident in Cagliari (Sardinia, Italy), was divided into two groups: active and inactive. Twenty-five anthropometric dimensions were taken (weight, lengths, breadths, circumferences, and skinfolds). The circumferences and skinfolds were adjusted for the effects of overall body size (represented by skeletal variables). Body composition parameters-fat-free mass (FFM), fat mass (FM), and arm muscular area (AMA)-were derived from the adjusted values. The D index (Bennett, 1981; Chakraborty and Majumder, 1982) was used to assess the degree of sexual dimorphism. The difference between the D values of active and inactive individuals was analyzed with the technique of Bennett (1981). Principal components analysis (PCA) was performed on groups of homogeneous variables (circumferences and skinfolds) in order to simplify the description of the original anthropometric data. The univariate and multivariate analyses indicate a greater sex difference in the group of individuals who are regularly active. The results agree with theoretical expectations, and suggest greater stability of women to environmental pressures (i.e., physical activity). (C) 2001 Wiley-Liss. Inc
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